Bump gradle-build-action to v3

Gradle v2 uses node16 which will be EOL soon.

"The only major breaking change from gradle-build-action@v2.12.0
is the update to require a Node 20 runtime environment.

Aside from that change, this release should generally serve as a
drop-in replacement for gradle-build-action@v2."

Gradle updated the action name, following the advice from
https://github.com/gradle/gradle-build-action/releases/tag/v3.0.0

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
   #     run: git submodule init && git submodule update
 
   #   - name: Setup Gradle
-  #     uses: gradle/gradle-build-action@v2
+  #     uses: gradle/actions/setup-gradle@v3
 
   #   - name: Cache NuGet packages
   #     uses: actions/cache@v3
@@ -136,7 +136,7 @@ jobs:
   #     run: git submodule init && git submodule update
 
   #   - name: Setup Gradle
-  #     uses: gradle/gradle-build-action@v2
+  #     uses: gradle/actions/setup-gradle@v3
 
   #   - name: Cache NuGet packages
   #     uses: actions/cache@v3
@@ -257,7 +257,7 @@ jobs:
     - uses: actions/checkout@v4
 
     - name: Setup Gradle
-      uses: gradle/gradle-build-action@v2
+      uses: gradle/actions/setup-gradle@v3
 
     - name: Cache NuGet packages
       uses: actions/cache@v3